In today's integrated radio frequency (RF) transceivers, stages in the upconversion and downconversion of signals typically introduces unwanted harmonics. In upconverting a baseband signal for transmission at RF, a baseband filter and mixer typically introduce unwanted harmonics into the upconverted signal. Such unwanted harmonics typically degrades adjacent channel leakage ratio (ACLR) performance of a transmitter and/or introduces in-band distortion, for example.
Techniques to reject unwanted harmonics have typically included implementation of a three-phase harmonic rejection mixer (HRM). For the upconversion of a baseband waveform for RF transmission, for example, a HRM typically mixes the baseband waveform with three different local oscillator (LO) signals, and combines the resulting mixed signals to remove unwanted harmonics. Such a technique would typically be implemented in circuitry using three mixers and three phasors for mixing the baseband waveform. As such, this particular technique impacts power consumption and silicon (e.g., CMOS) processing requirements (e.g., for implementation of RF devices in CMOS).